Method for prefetching external resources to embedded objects in a markup language data stream

Abstract

A method of outputting a document on a rendering engine in a client in a computer network. The document comprises a markup language data stream having a plurality of references to external resources required by the document. In operation, the document is first retrieved to the client. As the document is received, the rendering engine parses the markup language data stream for a list of external resources. If the list of external resources is present in the markup language data stream, the engine selectively prefetches at least one external resource as the document is output by the rendering engine.

What is claimed is:  
     
       1. A method of outputting a document, the method comprising: 
       retrieving the document at a client from a server, wherein the document comprises a markup language data stream having a plurality of references to external resources required by the document, wherein the markup language data stream comprises a list of external resources that is positioned in the data stream before all of the references to external resources prior to receipt of the markup language data stream at the client, wherein each external resource in the list of external resources is prioritized according to a priority scheme, and wherein the priority scheme allows for prioritization based on resource type;  
       parsing the markup language data stream for the list of external resources;  
       determining whether prefetching of external resources is enabled prior to prefetching any external resources in the list of external resources; and  
       if prefetching of external resources is enabled, selectively prefetching at least one external resource as the document is output by the rendering engine.  
     
     
       2. The method as described in  claim 1  wherein, according to the priority scheme, a given first external resource is prefetched before a given second external resource. 
     
     
       3. The method as described in  claim 1  wherein, according to the priority scheme, a given first external resource type is prefetched before a given second external reference type. 
     
     
       4. The method as described in  claim 1  wherein the at least one external resource is prefetched by having the rendering engine start an additional processing thread. 
     
     
       5. The method as described in  claim 1  wherein the rendering engine is a browser. 
     
     
       6. The method as described in  claim 1  wherein the rendering engine is a graphics display viewer. 
     
     
       7. A method of outputting a document on a rendering engine in a client, the document comprising a markup language data stream having a plurality of references to external resources required by the document, comprising the steps of: 
       retrieving the document;  
       parsing the markup language data stream for a list of external resources;  
       if the list of external resources is present in the markup language data stream, determining whether prefetching of external resources is enabled prior to prefetching any external resources in the list of external resources;  
       if prefetching of external resources is enabled, selectively prefetching a given external resource;  
       caching the given external resource;  
       determining whether a reference to the given external resource has been reached in the markup language data stream;  
       if so, retrieving the given external resource from cache, if available; and  
       outputting the given external resource.  
     
     
       8. The method as described in  claim 7  wherein the given external resource is prefetched by having the rendering engine start an additional processing thread. 
     
     
       9. The method as described in  claim 7  wherein the rendering engine is a browser. 
     
     
       10. The method as described in  claim 7  wherein the rendering engine is a graphics display viewer. 
     
     
       11. The method as described in  claim 7  wherein the given external resource has a priority value associated therewith. 
     
     
       12. A method for enhancing the performance of a client rendering engine, comprising the steps of: 
       receiving a markup language data stream defining a page;  
       outputting the page on the client rendering engine;  
       determining whether prefetching of external resources is enabled prior to prefetching any external resources in an external resource list; and  
       if prefetching of external resources is enabled, asynchronously prefetching a given external resource in the page based on the external resource list selectively positioned in the markup language data stream.  
     
     
       13. The method as described in  claim 12  further including the step of storing the given external resource. 
     
     
       14. The method as described in  claim 13  further including the step of retrieving and outputting the given external resource when a reference to that resource is encountered in the markup language data stream. 
     
     
       15. The method as described in  claim 12  wherein the external resource list is positioned in the data stream before an initial object reference to one of the external resources in the list. 
     
     
       16. A computer program product in a computer-readable medium, comprising: 
       a rendering engine for receiving a markup language data stream and outputting a page;  
       program instructions for determining whether prefetching of external resources is enabled prior to prefetching any external resources in a list of external resources; and  
       program instructions for asynchronously prefetching external resources required by the page according to the a list of external resources included in the markup language data stream if prefetching of external resources is enabled.  
     
     
       17. A computer connectable to a computer network having at least one origin server, the computer comprising: 
       a processor;  
       a rendering engine for receiving a markup language data stream and outputting a page;  
       program instructions for determining whether prefetching of external resources is enabled prior to prefetching any external resources in a list of external resources; and  
       program instructions for asynchronously prefetching external resources required by the page according to the list of external resources included in the markup language data stream if prefetching of external resources is enabled.